Molded egg carton

ABSTRACT

A molded egg carton has a latch flap extending from the base and disposed to tuck inside the cover and interlock with a latch region of the cover, and the flap and cover respectively carry a male member with oblique side surfaces and a female member with gripping surfaces for engaging the male surfaces to latch the cover down.

United States Patent 1 1 3,563,450

[72] Inventor Kurt G. Dahlberg [56] References Cited Rpchester, N.Y. (71 Stuyvesant Road, UNITED STATES PATENTS [21] A I No gmg 14534) 2,843,304 7/1958 Reifers 229/4sx 3 3,289,911 12/1966 Boyd et a1 229/45x [22] Flled Jan. 2, 1969 [45] Patented Feb 16 1971 3,337,110 8/1967 Comm1ssoeta1.. 229/45X 3,371,848 3/1968 Ward et a1. 229/45 Continuation of application Ser. No. 770,264 Oct 24 1968 h d 3,398,875 8/1968 Show et a]. 229/44X 3,441,196 4/1969 Burkett 229/44 3,465,947 9/ 1 969 Andrews, et a1. 229/44 Primary Examiner-Davis T. Moorhead Attorney-Cumpston, Shaw & Stephens [54] MQLDED EGG CARTON ABSTRACT: A molded e carton has a latch flap extending 6 Chums l3 Drawmg Flgs' from the base and disposed to tuck inside the cover and inter- [52] US. Cl 229/44, lock with a latch region of the cover, and the flap and cover 22 respectively carry a male member with oblique side surfaces [51] Int. Cl. B65d 5/66 and a female member with gripping surfaces for engaging the [50] Field of Search 229/44, 45 male surfaces to latch the cover down.

PATENIE'DFEBIBIQYI 3563x150 SHEU'I [1F 2 INVENTOR. KURT G. DAHLBERG BY fmww.

ATTORNEYS PATENTEU FEB 1 6 IQYI SHEET 2 OF 2 FIG- IO FIG. I!

INVENTOR. KURT e. DAHLBERG M W I ATTORNEYS MOLDED EGG CARTON This application is a continuation-in-part of my copending parent application, Ser. No. 770,264, filed Oct. 24, 1968 abandoned as of the filing of this continuation-in-part application.

TI-IE IMPROVEMENT EFFECTED Modern, commercial requirements for egg cartons include mass production at low prices, filling, closing and packaging by automatic machinery, and ample protection for the fragile eggs. The prior art offers a variety of compromise solutions to these requirements, but the invention meets the requirements for economy and machine handling and improves over previous solutions by providing a more attractive egg carton with a better latch and a stronger cover that is rigidly braced over the base for maximum protection of the eggs.

The objects of the invention include, without limitation:

a. a strong and secure egg carton latch that holds the cover firmly closed and yet is easily manipulated to open and close the carton;

b. an egg carton cover that is well braced over the base to permit stacking of loaded cartons; and

c. combining the above features in an economical, mass production egg carton that can be loaded and packaged by automatic machinery.

These and other objects of the invention will be apparent hereinafter from the specification which describes the invention, its use, operation, and preferred embodiment, from the drawings which constitute a part of the disclosure, and from the subject matter claimed.

SUMMARY OF THE INVENTION The inventive egg carton latch includes: a latch flap extending outward from a fold line along the closing edge of the base portion of the carton, the flap being disposed inside the latch region of the cover when the carton is closed; male and female interlocking latch members carried on the flap and the cover, the male member having a pair of male surfaces perpendicular to the adjacent carton surfaces, oblique to each other and extending away from the closing edges of the carton and toward the female member which has a pair of gripping surfaces perpendicular to the adjacent carton surfaces and aligned with the male surfaces when the carton is closed; the flap being arranged to bring the gripping surfaces into engagement with the male surfaces when the cover is closed; and the obliqueness of these surfaces being oriented to diverge in the direction of opening of the portion of the carton carrying the female member to form a latching interlock with a wedging action.

THE DRAWINGS FIG. I is a plan view of a preferred embodiment of the inventive egg carton;

FIG. 2 is a perspective view of the egg carton of FIG. 1 with the cover closed and latched;

FIG. 3 is a fragmentary cross-sectional view of the carton of FIG. 2 taken along the line 3-3 thereof;

FIG. 4 is a fragmentary cross-sectional view of the carton of FIG. 2 taken along the line 4-4 thereof and showing a finger releasing the latch;

FIG. 5 is a fragmentary cross sectional view of the carton of FIG. 2 taken along the line 5-5 thereof;

FIG. 6 is a fragmentary cross-sectional view of the latch of FIG. 3 taken along the line 6-6 thereof;

FIG. 7 is a fragmentary elevational view of an alternative latch arrangement for the inventive carton;

FIG. 8 is a fragmentary cross-sectional view of another alternative latch arrangement for the inventive carton;

FIG. 9 is a fragmentary elevational view of the latch of FIG.

FIG. 10 is a fragmentary elevational view of an alternative preferred latching arrangement for the inventive carton showing the latch in open position;

FIG. 11 is a fragmentary elevational view of the latch of FIG. 10 in the closed position; and

FIGS. 12 and 13 are fragmentary cross-sectional views of the latch of FIGS. 10 and 11 shown respectively in the closing and closed positions.

DETAILED DESCRIPTION The egg carton 10 shown in FIGS. l5 is one preferred embodiment of the invention. It includes a schematically illustrated base portion 11 compartmented for receiving eggs, and a cover portion 12 for closing over base 11. Carton I0 is molded in a single piece, preferably in the flat orientation illustrated in FIG. 1 and is formed of foamed resin material, pulp, or other material suitably strong and protective of the eggs. A hinge line 13 between base 11 and cover 12 allows cover 12 to fold over base 11 to close a carton 10 as illustrated in FIG. 2. Such folding brings the closing edge M of cover 12 down over the closing edge 15 of base 11 so that the closing edges 14 and 15 are close together in mutual registry.

A latch flap 16 extends normally outward from a fold line 17 along the closing edge 15 of base 11. In use, latch flap 16 is folded along line 17 inward to tuck inside cover 12 as the carton is closed. The normal bias of latch flap 16 is then outward against the inside of cover 12. Latch flap 16 includes a pair of male projections 18 extending outward toward the inside of cover 12 as best shown in FIGS. 3, 4, and 5. As best shown in FIG. 6, the side surfaces 19 of projection 18 are perpendicular to the general plane of latch flap l6, oblique to each other, and extend away from closing edge 15 to diverge with increasing distance from closing edge 15.

The inside surface of cover 12 adjacent closing edge 14 is formed as a latch region 20 for interlocking with latch flap I6. Latch region 20 has a pair of female recesses 21 generally aligned with projections 18. The side surfaces 22 of recesses 21 are generally perpendicular to the plane of latch region 20 and are mutually oblique to align with and grip side surfaces 19 of projections 18 in a wedging engagement that holds carton 10 closed. Gripping surfaces 22 are thus oblique and divergent with increasing distance from closing edge 14 of cover 12.

The top surfaces 23 of projections 16 are generally perpendicular to the plane of latch flap l6 and face away from closing edge 15 of base 11. Corresponding, opposed surfaces 24 of recesses 21 are perpendicular to the plane of latch region 20 and face downward toward closing edge 15 of base 11 when carton 10 is closed. As best shown in FIGS. 3 and 6, surfaces 23 and 24 engage when carton I0 is closed to brace cover 12 over base 11.

As best shown in FIGS. 2 and 4, a pair of slits 25 extend inward from closing edge 14 of cover 12 into latch region 20. A tab of material 46 between slits 25 then serves as a movable finger pressure tab as best shown in FIG. 4 for pressing inward against latch flap 16 between projections 18 to move latch flap I6 inward to release the interlocking latch between projections 18 and recesses 21 for opening the carton.

In the operation of carton 10, base 11 is filled with eggs, flap 16 is folded inward, and cover 12 is folded down over flap 16. When the carton is sufficiently closed, gripping surfaces 22 of recesses 21 straddle side surfaces 19 of projections 18, and flap 16 springs outward toward latch region 20 to be bring gripping surfaces 22 into secure engagement with side surfaces 19. The obliqueness of gripping surfaces 22 and side surfaces 19 is oriented so that their wedging interengagement prevents opening of cover 12.

As loaded cartons are stacked, cover 12 is pressed downward against base 11, and is braced by the engagement of recess surface 24 resting atop projection surface 23. As cover 12 is forced downward under such load, gripping surfaces 22 move downward and loosen their grip on side surfaces 19. This does not release the latch, however, since latch flap 16 is biased outward against latch region 20 to keep gripping surfaces 22 loosely astraddle side surfaces 19. When the downward load on cover 12 is removed, cover 12 tends to spring upward and this reengages the secure grip of surfaces 22 against surfaces 1'9. To open the carton, tab 46 is pressed inward as shown in FIG. 4, to push surfaces 19 inward from the grip of surfaces 22 to release the latch.

FIGS. 7-13 show some alternative to the carton of FIGS. 1-6. The carton of FIG. 7 has a latch flap 26 similar to latch flap 16 and provided with projections 18 as previously described. In place of recesses 21, the latch region 20 of the cover of the carton of FIG. 7 has open slots or notches 27 having oblique side edges or surfaces 28 for engaging the side surfaces 19 of projections 18 and transverse top surfaces 29 to rest against the tops 23 of projections 18 to brace the cover over the base ofthe carton.

For an alternative latch release, the central portion of latch flap 26 extends upward to form a pressure tab 30, and a resistered cutout opening 31 in latch region 20 allows finger access to pressure tab 30 for pushing latch flap 26 inward to release the interlock between projections 18 and slots 27. Another alternative to the pair of slits 25 and movable tab 26, is a single slit 25 allowing the flexible material of the latch region 20 of cover 12 to be bent inward at slit 25 for pressing latch flap 16 inward to release the latch.

FIGS. 8 and 9 show a reversal of the male and female latch parts of the carton of FIGS. 1-6. Thus recesses 35 are formed in latch flap 36, and corresponding projections 37 are formed in the latch region 38 of the cover of the carton. Projections 37 and recesses 35 are shaped respectively like projections 18 and recesses 21 previously described but are both inverted. Such inversion allows the oblique surfaces of recesses 35 to diverge in the direction of opening of the latch fiap 36 to form a latching interlock with projections 37.

The carton 40 of FIGS. -11 has a latch flap 41 similar to latch flaps 16 and 26 described above and bearing a pair of projections 42 forming male latch members. The female latch members are formed as notches 43 in the latch region of the cover portion of carton 40. Projections 42 each have a male surface 47 extending outward from the general plane of latch flap 41 toward the inside of carton 40. Male surfaces 47 are generally perpendicular to the plane of latch flap 41 and are oblique to each other as illustrated. Corresponding gripping surfaces 48 of notches 43 are aligned with male surfaces 47 for a wedging interlock such as shown in FIG. 11.

Projections 42 have top surfaces 49 that align with the top edges 50 of notches 43 to provide a support for the carton of carton 40. When edges 50 rest on top surfaces 49 as shown in FIG. 11, they brace the cover of carton 40. The uppermost corners 51 of projections 42 are rounded or sloped to allow camming of the cover of carton 40 over projections 42. Such action is shown in FIG. 12 as the cover ofcarton 40 is lowered into a latched position illustrated in FIG. 13.

A finger access arrangement such as described above can be used with carton 40 to push latching flap 41 inward to release the wedging latch. Carton 40, like the alternatives previously described, uses a wedging or side gripping interlock between male and female members to latch the carton cover down, and includes opposed confronting surfaces that brace the cover against weight from above. Also like the previous embodimerits, the parts ofthe latch of carton 40 can be reversed, multiplied, or interchanged.

Persons wishing to practice the invention should remember that other embodiments and variations can be adapted to particular circumstances. Even though one point of view is necessarily chosen in describing and claiming the invention, this should not inhibit broader or related applications within the spirit of the invention. For example, different numbers of latch projections and recesses can be used, the latch flap and cover can each carry both projections and recesses, latch members need not have the illustrated symmetrical trapezoidal shape, latch flaps can be longer or can extend further above the base, support and rest surfaces to brace the cover can be separated from the latch surfaces, and the carton can be shaped to hold eggs in a 3 X 4 arrangement rather than a 2 X 6 pattern.

I claim:

1. An improved latch for a single-piece egg carton having a base (portion shaped for receivin eggs and a cover portion ome to said base portion for fol mg over said base portion to close said carton with the closing edges of said base portion and said cover portion close together in mutual registry, said latch comprising:

a. a latch fiap extending normally outward from a fold line along said closing edge of said base portion;

b. in the closed condition of said carton, said latch flap being normally disposed inside and generally parallel with a latch region of said cover portion adjacent said closing edge of said cover portion;

0. a pair of projections on said latch flap extending outward from the general plane of said latch flap toward said latch region of said cover portion in said closed condition of said carton;

. said projections having side surfaces perpendicular to the parallel planes of said latch flap and said latch region in said closed condition of said carton;

. said side surfaces being oblique to each other and extending generally away from said closing edges of said carton; a pair of open notches extending from said closing edge of said cover portion inward into said latch region of said cover portion.

g. said notches having side edges oblique to each other and registering with said side surfaces of said projections in said closed condition of said carton; and

. said side edges and side surfaces being angled relative to said closing edges of said carton to wedge against each other to resist the openings of said carton.

2. The carton of claim 1 wherein said latch region of said cover portion is formed with a slit extending upward from said closing edge of said cover portion to allow finger pressure to move said fiap inward to disengage said side edges and side surfaces.

3. The carton of claim 2 including a pair of said slits spaced apart by at least finger width.

4. The carton of claim 1 wherein each of such projections has a pair of said oblique side surfaces, and each of said notches has a corresponding pair of said oblique side edges.

5. The carton of claim 1 wherein said projections include top surfaces generally perpendicular to the plane of said latch flap, and said notches have top edges adjacent said top surfaces of said projections in said closed carton condition for supporting said cover over said base.

6. The carton of claim 5 wherein said projections are shaped for camming engagement with said latch region of said cover portion as said carton is closed. 

1. An improved latch for a single-piece egg carton having a base portion shaped for receiving eggs and a cover portion joined to said base portion for folding over said base portion to close said carton with the closing edges of said base portion and said cover portion close together in mutual registry, said latch comprising: a. a latch flap extending normally outward from a fold line along said closing edge of said base portion; b. in the closed condition of said carton, said latch flap being normally disposed inside and generally parallel with a latch region of said cover portion adjacent said closing edge of said cover portion; c. a pair of projections on said latch flap extending outward from the general plane of said latch flap toward said latch region of said cover portion in said closed condition of said carton; d. said projections having side surfaces perpendicular to the parallel planes of said latch flap and said latch region in said closed condition of said carton; e. said side surfaces being oblique to each other and extending generally away from said closing edges of said carton; f. a pair of open notches extending from said closing edge of said cover portion inward into said latch region of said cover portion. g. said notches having side edges oblique to each other and registering with said side surfaces of said projections in said closed condition of said carton; and h. said side edges and side surfaces being angled relative to said closing edges of said carton to wedge against each other to resist the openings of said carton.
 2. The carton of claim 1 wherein said latch region of said cover portion is formed with a slit extending upward from said closing edge of said cover portion to allow finger pressure to move said flap inward to disengage said side edges and side surfaces.
 3. The carton of claim 2 including a pair of said slits spaced apart by at least finger width.
 4. The carton of claim 1 wherein each of such projections has a pair of said oblique side surfaces, and each of said notches has a corresponding pair of said oblique side edges.
 5. The carton of claim 1 wherein said projections include top surfaces generally perpendicular to the plane of said latch flap, and said notches have top edges adjacent said top surfaces of said projections in said closed carton condition for supporting said cover over said base.
 6. The carton of claim 5 wherein said projections are shaped for camming engagement with said latch region of said cover portion as said carton is closed. 